X-ray pure yttrium diborodicarbide (YB 2 C 2) was synthesized for the first time via modified spark plasma sintering (SPS) using Y 2 O 3 , B 4 C, and carbon as starting materials. Homogeneous intermixing of the raw powder by high energy ball milling (HEBM) promoted the formation of YB 2 C 2 powder with layered structure by boro/ carbo-thermal reduction. The average particle size of the synthesized powder at an optimum synthesis temperature (1625℃) was 568 nm. Small amount of YB 2 C was formed by consuming YB 4 at and above 1625°C. The metal basis purity of the synthesized YB 2 C 2 powder was 99.84%. X-ray pure YB 2 C 2 was obtained by densifying the synthesized YB 2 C 2 powder at 1900°C for 60 minutes at a pressure of 80 MPa using SPS. This study reports a simple method for the fabrication of X-ray pure rare earth metal diborodicarbides (ReB 2 C 2). K E Y W O R D S high energy ball milling, powder, spark plasma sintering, yttrium diborodicarbides 1230 | NGUYEN Et al.